1. Field of the Invention
The present invention relates to a steering member unit for a vehicle.
2. Description of the Related Art
In vehicles such as automobiles, an instrument panel is provided in a front part inside a cabin. A vehicle body reinforcement member that supports a steering column is provided within the instrument panel (for example, see Japanese Patent Application Publication No. 2001-10509).
Since the vehicle body reinforcement member supports the steering column, the vehicle body reinforcement member is referred to as a steering member or the like.
As shown in FIG. 2, a conventional steering member 1 includes a metal steering member body 3 disposed to extend in the front part of the cabin substantially in a vehicle width direction 2, metal side brackets 5 that are fixed respectively to both ends of the steering member body 3 and are attachable respectively to vehicle body side parts 4, and metal stays 7 that are fixed to a substantially intermediate part of the steering member body 3 and are attachable to a vehicle body floor 6.
In the conventional steering member 1, the metal steering member body 3 is disposed in the front part within the cabin, and the metal side brackets 5 fixed respectively to both ends of the steering member 1 are attached respectively to the vehicle body side parts 4. In addition, the metal stays 7 fixed to the intermediate part of the steering member body 3 are attached to the vehicle body floor 6. Thereby, the steering member 1 is attached to a vehicle body.
To the steering member 1 thus attached to the vehicle body, a steering column, various kinds of interior parts 8 and 9, and the like are attached with unillustrated metal brackets for attachment. The steering member 1 is finally covered with an instrument panel so as to be hidden to be invisible from the outside.
However, in the above-mentioned structure, a ground current 11 is generated in the steering member 1, or a motor, an electronic circuitry or the like of the interior parts 8 and 9 provided near the steering member 1. The generated ground current 11 flows into the steering member body 3 through the side brackets 5, the stays 7, other unillustrated metal brackets, and the like.
When the current (ground current 11) flows into the steering member body 3, a magnetic field 12 is generated, and resonance of a wavelength depending on a distance (length) of the flowing current (ground current 11) is generated in the steering member body 3. In this case, the resonance frequency of the wavelength has a magnitude depending on a length of the steering member body 3, a distance between the side bracket 5 and the stay 7, or the like.
The resonance frequency f of the wavelength generated in the steering member body 3 is generally obtained with a formula of λ (length)/4=3×10^8 (m/s)/f. Here, supposing that the distance between the side bracket 5 and the stay 7 is 1.0 m, it is found from the above-mentioned formula that the largest resonance takes place at approximately 125 MHz. In this case, since there is an influence of resonance up to λ/10 (approximately 30 MHz), poor reception occurs in a (FM) radio reception frequency band.
Accordingly, in the above-mentioned conventional steering member, in order to eliminate such poor reception, a noise filter has been provided, for example. However, since the noise filter is expensive, there has been a problem of increase in cost.